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Add hooks for type-specific calculation of ANALYZE statistics. Idea and

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coding by Mark Cave-Ayland, some kibitzing by Tom Lane.  initdb forced
due to new column in pg_type.
This commit is contained in:
Tom Lane
2004-02-12 23:41:04 +00:00
parent d27471fe0a
commit 69946411d3
13 changed files with 740 additions and 501 deletions
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9
doc/src/sgml/catalogs.sgml
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@ -1,6 +1,6 @@
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
$PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.82 2004/01/06 23:55:18 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.83 2004/02/12 23:41:00 tgl Exp $
-->
<chapter id="catalogs">
@ -3524,6 +3524,13 @@
<entry>Output conversion function (binary format), or 0 if none</entry>
</row>
<row>
<entry><structfield>typanalyze</structfield></entry>
<entry><type>regproc</type></entry>
<entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
<entry>Custom ANALYZE function, or 0 to use the standard function</entry>
</row>
<row>
<entry><structfield>typalign</structfield></entry>
<entry><type>char</type></entry>

31
doc/src/sgml/ref/create_type.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.48 2003/11/29 19:51:38 pgsql Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.49 2004/02/12 23:41:02 tgl Exp $
PostgreSQL documentation
-->
@ -28,6 +28,7 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> (
OUTPUT = <replaceable class="parameter">output_function</replaceable>
[ , RECEIVE = <replaceable class="parameter">receive_function</replaceable> ]
[ , SEND = <replaceable class="parameter">send_function</replaceable> ]
[ , ANALYZE = <replaceable class="parameter">analyze_function</replaceable> ]
[ , INTERNALLENGTH = { <replaceable class="parameter">internallength</replaceable> | VARIABLE } ]
[ , PASSEDBYVALUE ]
[ , ALIGNMENT = <replaceable class="parameter">alignment</replaceable> ]
@ -83,8 +84,9 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> (
<replaceable class="parameter">input_function</replaceable> and
<replaceable class="parameter">output_function</replaceable>
are required, while the functions
<replaceable class="parameter">receive_function</replaceable> and
<replaceable class="parameter">send_function</replaceable>
<replaceable class="parameter">receive_function</replaceable>,
<replaceable class="parameter">send_function</replaceable> and
<replaceable class="parameter">analyze_function</replaceable>
are optional. Generally these functions have to be coded in C
or another low-level language.
</para>
@ -152,6 +154,19 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> (
shell entry with a complete type definition, and the new type can be used.
</para>
<para>
The optional <replaceable class="parameter">analyze_function</replaceable>
performs type-specific statistics collection for columns of the data type.
By default, <command>ANALYZE</> will attempt to gather statistics using
the type's <quote>equals</> and <quote>less-than</> operators, if there
is a default b-tree operator class for the type. For non-scalar types
this behavior is likely to be unsuitable, so it can be overridden by
specifying a custom analysis function. The analysis function must be
declared to take a single argument of type <type>internal</>, and return
a <type>boolean</> result. The detailed API for analysis functions appears
in <filename>src/include/commands/vacuum.h</>.
</para>
<para>
While the details of the new type's internal representation are only
known to the I/O functions and other functions you create to work with
@ -341,6 +356,16 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> (
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">analyze_function</replaceable></term>
<listitem>
<para>
The name of a function that performs statistical analysis for the
data type.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">internallength</replaceable></term>
<listitem>